low oil pressure or bad dummy gauge

94TramsAmGT · #1 06-04-2006, 11:56 PM

When i first start my car up my oil pressure is reading about 45-50 which is in reason. It stays right around 40 obviously going up as i accelerate. however, once my car warms up i lose pressure drastically. when running at a constant speed of 55-60 mph my reading is only 30. I know this is not horrible, but if i let off the gas and coast once the car gets to 35 mph the reading drops to 20. As i am sitting, idling (this is after the car is warmed up) my reading is below 20, but not in the red line. when i take off it jumps back up to 30-35 but will not go past 40. every once in a while when i am stopped i smell what appears to be "burnt" oil. i have no visible leaks, and my oil looks fine. Its not all black and slugdey looking. So is this my pump going bad or maybe just my gauge. i was planning on taking this car on a long trip in a month but now im unsure. Is this reading im getting ok for me to drive the car or am i just asking for trouble? How can i go about checking my pressure externally? Please help, oh yeah by the way its a 94 TA with 104k. thank you

94TramsAmGT · #2 06-05-2006, 11:02 PM

so i get snubbed again, isn't there anyone out there that can help me with this... I don't really want to spend the $$ taking it to a dealer, so any advice would be great. thanks

ikeyballz · #3 06-06-2006, 01:10 AM

you have an LT1 right? mine does the same thing..and as i recall, people told me that it was fine. =) it all depends on the RPMS of the engine, not the speed of the car.. however..i AM going to try to do a full engine flush + fill her up with royal purple oil..ill tell you how that goes!

ikeyballz · #4 06-06-2006, 01:10 AM

btw, the 20~ is almost at idle right? even when youre coasting, its because its around idle..

ikeyballz · #5 06-06-2006, 01:12 AM

oh..and..heres the link for mine.. 95, be patient..just wait a little. everyone else is busy sometimes :]

http://www.automotiveforums.com/vbul...d.php?t=567408

94TramsAmGT · #6 06-06-2006, 02:10 AM

yes it's the LT1 and yeah it drops below 20 at idle, but only after it is warm. Even when i floor it after it is warm i can't get a reading over 40. It use to read about 60 when i tromped on her. mine actually drops to about 12-14 when sitting/idling in gear. not quiet in the red but damn close. It definetly can't be good on the motor to go from a 14 psi idling to WOT. it's really irritating, because when she was like new it alwasys kept at least 40 psi all the time. starting to get worried. Another weird thing, everytime i change oil and fire it up i get a reading of about 60-65 for about 2 minutes then drops to 40. I thought maybe the screeen on the pump was clogged, but like i said my oil isn't dirty at all. Confused, so yeah i would appreciate it if you let me know what you find out about your car. thanks so much for the reply.

ikeyballz · #7 06-06-2006, 09:57 PM

hehe no probs. i heard that the oil pressure is governed not by the oil pump but by the spring that holds the pressure in, so if that spring is weak for yours..it might explain the low pressure..

superducky55 · #8 06-07-2006, 06:09 PM

I have a 95 lt1 v8 formula does the same thing, though not as dramatic as yours. 20 ish at idle. I'm pretty sure its normal.
Yours does sound like it may even be a little too much fluctuation.. I'd say wait and get a few more opinions on here before you take it in just yet.

crank182 · #9 06-07-2006, 08:21 PM

I have a 95 formula does the same thing. Stays just above 20 at idle. I've heard this is a common problem but nothing to worry about from quite a few people. As long as the oil is changed regularly and it doesn't make any valvetrain clicking it should be fine.

94TramsAmGT · #10 06-07-2006, 11:32 PM

i have had a lot of people tell me it's no big deal, which is good news, but still something has to be causing it. And im not sure if i'm paranoid or what, but the last few days when i have popped the hood i do hear unusually loud clicking. coming from the passenger side, but ive alwasy noticed this just seems louder than before. like i said i could just be paranoid and think its worse. I think this noise is just the injectors clicking, but like i said one side is louder than the other. I ordered a knock sensor, but i'll be damned cuz i can't find where it is. I thought it was near the back on passenger side but can't find it. anyone know where it is? going to get a new sending unit and try that also. ickeyballs mentioned that the spring controls the pressure, this is the one on the pump right? well once again thank you and any more suggestions would be great.

ikeyballz · #11 06-08-2006, 01:24 AM

so, i changed my oil..and the pressure doesnt change, so im guessing its just like that. i wouldnt worry about it too much..unless someone else has a diff opinion.

doodad · #12 06-08-2006, 02:13 AM

mine is excatly the same.. when the car is cold it is like 45-50 and when the car warms up it is like 30ish.. well because of weak valve cover gasket l lost some oil, l dont know if that effected but today l put some oil and tomorrow l will see if the gauge is still the same.. my car runs fine..

superducky55 · #13 06-08-2006, 09:57 AM

Here's a page with component locations for everything important
knock sensor is on there.
kudos to this rob guy for the sweet site. spread it around

http://shbox.com/1/4th_gen_tech1.html

94TramsAmGT · #14 06-12-2006, 10:58 PM

well i have an update on my situation. changed the oil sending unit over the weekend and my pressure reading improved. now after it is warmed up and idling it is reading about 22. not what i wanted, but better than the 14 or so i was getting, so i am guessing that my gauge is just screwed up. Would i need to just get a new gauge, because im not sure there is anything i can do with it being electronic.(any way to adjust it) it's not really that big of a deal, but i do feel better about the car. thanks to all for your help.

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